1. Field of the Invention
The present invention relates to a display apparatus for a single lens reflex camera of the type having an interchangeable lens, and more particularly to such a display apparatus for displaying dimensions of a subject.
2. Description of the Prior Art
Conventionally, various parameters, such as shutter speed, an F-stop value, etc., which are necessary for taking a photograph are displayed in the viewfinder in a prior art single-lens reflex camera, such as one of the prior art manual types. With the proliferation of autofocus and autoexposure single-lens reflex cameras commercially available today, the contents of the display in the viewfinder of such a single-lens reflex camera has increased to display such other factors as stroboscope charging-up operation completion, in-focus condition confirmation, etc.
For many years, there has existed a need to know the distance to a subject or the size of a subject. In one such prior art method of measuring a subject distance using a single-lens reflex camera, the subject distance is obtained by the use of a distance scale mark on the interchangeable lens after the focus adjustment has been completed. The size of the subject can also be obtained by reading scale marks indicative of a height and a width on a finder picture, with these seale marks being formed near the distance scale marks on the interchangeable lens. In such a prior art conventional method, however, since the focus is adjusted manually, there exists various drawbacks in that there is a difference between individuals and additionally there is an error according to the focal distance of the lens. Further, in the case where such means is applied to a zoom lens, it is impossible to display the size of a subject because the size corresponding to the finder picture changes according to the focal distance. These disadvantages of the prior art are overcome by the present invention.